Frozen dairy dessert products such as ice cream, ice milk, milk shakes, sherbet, yogurt, sorbet and the aerated versions thereof, are popular due to their convenience, wide spread availability, nutritive value and appealing forms, flavors, and colors. Such dairy desserts may range in fat content from 0.01-18 wt-%. A weight conscious society has further popularized non-fat and low fat preparations. In addition to consumer expectations of flavor, appearance, and in particular the physical properties of embodiments such as aerated frozen dessert products, the nature and composition of these products are regulated by various standards of identity promulgated by the U.S. Food and Drug Administration and the individual states. The combination of rigid consumer acceptance criteria, regulatory standards and the complex nature of the interactions which produce an acceptable frozen dessert product, make it difficult to formulate an aerated frozen dessert having improved characteristics, particularly when formulating a reduced or non-fat product containing only natural components and ingredients without added traditional stabilizing gums.
The foregoing factors are also true for quiescently frozen dairy dessert products such as ice cream bars, novelty dessert bars, yogurt bars, ice milk bars, fudge pops and the like. That is, it is difficult to formulate quiescently frozen desserts which have improved characteristics and which also contain only natural ingredients, contain no added stabilizers and have a reduced fat content.
It is particularly desirable for frozen dessert products to be stable against "heat shock," which is cyclic conditions of partial thawing and refreezing which occur during typical storage, shipping and handling of frozen dairy desserts. These cycles of fluctuating temperatures promote ice crystal growth in the dessert product, and a resultant gritty texture to the product. The gritty texture and mouthfeel, and diminished appearance detract from the overall general quality of the product.
Stabilizing gums and emulsifiers have been used in an attempt to improve the heat shock stability of frozen food products. Examples of stabilizing gums which have traditionally been used in ice cream include gum acacia, guar gum, locust bean gum, carrageenan, and the like. Often microcrystalline cellulose and carboxymethylcellulose are used in combination with the stabilizing gums to maximize their functional effectiveness. Emulsifiers help provide stability by facilitating the formation of an interface between the aqueous phase and the fat phase. Milk and egg yolks are both sources of natural emulsifiers. Commercially available emulsifiers are generally derived by chemical reaction with naturally occurring glycerides. See for example, U.S. Pat. No. 3,800,036 (issued Mar. 26, 1974) and U.S. Pat. No. 3,809,764 (issued May 7, 1974) to Gabby et al., and U.S. Pat. No. 4,552,773 to Kahn et al. (issued Nov. 12, 1985). In U.S. Pat. No. 4,400,405 to Morley et al. (issued Aug. 23, 1983), low fat aerated frozen soft-serve dairy desserts containing high levels of stabilizers, emulsifiers and polyhydric alcohols are provided. U.S. Pat. No. 4,497,841 to Wudel et al. (issued Feb. 5, 1985) discloses reduced fat, aerated frozen dairy desserts prepared with added whey protein concentrate to partially replace the milk solids non-fat, and containing fructose rather than sucrose as the sweetening agent, with added emulsifiers and stabilizers to improve the body and texture of the frozen desserts. U.S. Pat. No. 4,874,627 to Greig et al. (issued Oct. 17, 1989) discloses non-fat frozen dairy dessert compositions which incorporate stabilizers and contain at least some caramelized milk solids. In combination with stabilizers, high levels of corn syrup solids have been added to low-fat frozen dessert compositions in an attempt to avoid lactose crystallization and overcome sandiness from high lactose levels, as disclosed in U.S. Pat. No. 3,345,185 to Pisani et al. (issued Oct. 3, 1967).
Though gums improve stability, the use of gums presents several drawbacks. The quantity of stabilizing gums required to provide effective heat shock stability often produces a frozen dessert product which has an unacceptable greasy and/or gummy mouthfeel. In addition, although stabilizing gums may be derived from naturally-produced substances, consumers tend to perceive a product which contains gums to contain artificial rather than all natural ingredients.
Ultrafiltration of the milk component of dairy desserts has been used in an attempt to reduce lactose crystallization in the frozen dessert products. G.B. Pat. No. 1,444,143 to Aktiengesellschaft de Danske Sukkerfabrikker (Inventor O.J. Olsen; published Jun. 30, 1976) discloses preparing frozen desserts by subjecting skim milk or whey concentrate to ultrafiltration to concentrate the milk solids and reduce the ratio of lactose to milk protein, with the addition of stabilizers and emulsifiers to the dessert compositions.
U.S. Pat. No. 4,840,813 to Greenberg et al. (issued Jun. 20, 1989) also discloses low and non-fat dairy desserts prepared with ultrafiltered skim milk. To provide fat-like benefits for improved heat shock stability, high levels of whey protein concentrate, being at least 50% undenatured, are added to the compositions to provide a whey protein to casein ratio dramatically different than that observed in milk.
Therefore, an object of the present invention is to provide a composition comprising all natural ingredients without added stabilizing gums, which is capable of being processed into an aerated frozen dairy dessert product. Another object is to provide aerated frozen desserts which are heat shock stable over a range of fat content, and which have a high degree of creaminess, and organoleptic qualities comparable to high fat frozen desserts such as ice cream. Yet another object is to provide a method of making the dairy dessert compositions and frozen dairy dessert products of the invention. Yet another object of the invention is to provide a quiescently frozen dessert product with these characteristics.